Why go gluten free????

Why is gluten bad for you? I always see different foods promoted to be gluten-free, but why does that make it any healthier for you?? I always thought it was a dietary thing I never had to pay attention too, but I'm wondering if there is something more to this whole gluten-free thing. My roommate sometimes shares her gluten-free pasta and gluten-free ice cream with me and I don't know why....but either in a few hours or by that next morning, my system CLEANS itself. Usually I only go once a week. But whenever I eat gluten-free meals, I go! It makes me feel healthier, but is this from the gluten?? It's really making me considering to go gluten-free. But is this just a coincidence or is there something about gluten-free? (my roommate has celiac disease, which is why she eats gluten-free products).